1. Field of the Invention
The present invention relates to a liquid ejection apparatus and a maintenance method for a liquid ejection head, and more particularly, relates to liquid ejection head maintenance technology for an inkjet recording apparatus which forms an image on a medium by ejecting ink from a nozzle.
2. Description of the Related Art
In an inkjet recording apparatus which forms images on a recording medium by moving a recording medium and a head relatively to each other, if foreign matter such as ink or paper dust adheres to the nozzle forming surface (ejection surface) of the head or the interior of the nozzles (ejection holes), then it becomes difficult to sustain prescribed ejection characteristics and this leads to degradation of the quality of the recorded image. In order to solve problems of this kind, maintenance is carried out to remove foreign matter from the nozzle forming surface and the interiors of the nozzles.
Japanese Patent Application Publication No. 2005-144737 discloses an invention relating to an inkjet printer in which ink blockages in the ejection holes are avoided by performing a removal operation of spraying a cleaning liquid onto the ejection surface of the recording head, wiping the ejection surface with a blade and then ejecting ink from the ejection holes.
However, in a maintenance method which removes foreign matter on the nozzle forming surface by wiping the nozzle forming surface with a blade, air bubbles are incorporated inside the nozzles by the wiping action of the blade over the nozzle surface. If air bubbles are incorporated inside the nozzles, then during ink ejection for image formation, effects caused by the ejection pressure are absorbed by the air bubbles and this gives rise to ejection abnormalities, such as ejection failures, deviation of the ejection direction, and reduction in the volume of ejected liquid droplets. As one method for avoiding ejection abnormalities caused by incorporation of air bubbles in this way, purging (preliminary ejection) is carried out after wiping by means of a blade; however, a large volume of ink is required to be ejected to remove air bubbles from the interior of the nozzles, and therefore the ink consumption volume increases.
In the invention disclosed in Japanese Patent Application Publication No. 2005-144737, when the cleaning liquid is sprayed onto the ejection surface, the cleaning liquid directly infiltrates into the meniscus and therefore there is a possibility that air bubbles may become incorporated. Furthermore, since the ejection surface of the recording head is wiped by a blade after applying the cleaning liquid onto the ejection surface, then the deaeration level in the vicinity of the meniscus declines during the period from the spraying of the cleaning liquid until the wiping action.